When director Matt Reeves was hired, “Dawn of the Planet of the Apes” began with already-intelligent apes attacking a postapocalyptic San Francisco. But, says Reeves, “I thought it would be more exciting to not jump so far ahead.”

Now, “Dawn of the Planet of the Apes” begins with a long, nearly wordless segment featuring the apes, who are living outside of San Francisco. To learn how this society would function, Reeves and the crew studied primitive-human history.

Here are four elements of ape society:

Fire

Photo: 20th Century Fox

“The idea was this was a primitive society and they don’t need electricity or the shelter that we do,” Reeves says. “But that they’d still have fire to cook and illuminate that world was a conscious decision. It was no different from the idea of having a human tribe that would have fire.”

Language

Photo: 20th Century Fox

In the apes’ village, you see a wall with words and pictograms scratched on it: “We did research into tribal communication and the idea of pictograms,” Reeves says. “There are crude drawings, like of the Golden Gate Bridge, depicting their history from ‘Rise’ and their freedom from bondage.”

Shelter

Photo: 20th Century Fox

The apes are shown living in open-air treehouses that dot the canopy of their woodland home.

“We talked about how strong the apes are,” Reeves says. “We thought, they’re in the woods and they’re seven times stronger than we are, so couldn’t they tear down trees and begin fashioning these logs together?”

Weapons

Photo: 20th Century Fox

In the beginning of the movie, the apes hunt deer with spears. It’s only when they steal firearms that things really start to get dicey for the humans.

“I thought the tipping point [in the struggle between man and monkey] would be firearms,” Reeves says. “[A gun] would upset the balance of power.”